Servo Mounting Screws 9/16" length is perfect for mounting servos or any number of other uses in your aircraft.  Deep 5/64" socket head (hex/balldriver) prevents slipping and damaging your plane. $3.75  50pc
TYGON Fuel Line Buy it by the foot.  1/8" inner diameter.  1/4" outer diameter.  The perfect size for 50cc-150cc engines $1.00 per foot